Spark plug



Aug. 23,1938. w. HARPER, J 2,127,513

r SPARK PLUG Filed May 25, 1957 INVENTOR flzz/a/vAaipzi/ ATTORNEY Patented Aug. 23, 1938 2 UNITED STATES PATENT OFFICE SPARK PLUG William Harper,pJr., Port Washington, N. Y., as-

signor to H. B. Motor Corporation, New York, N. Y., a corporation of New York Application May 25, 1937, Serial No. 144,575

7 Claims. (01. 123-189) This invention relates to spark plugs and aims through the orifice IS in passing from the lower to provide a spark plug of great durability and to portion I4 to the upper portion it of the increase the efflciency in smoothness of operation chamber. It, therefore, flows more rapidly in the of internal combustion engines. orifice'than in the other parts of the chamber In accordance with the invention, these oband thus creates a zone of relatively low pres- 5 jects, as well as other advantages, are attained by sure at the orifice which surrounds the spark gap. providing means for creating a zone of relatively Most desirably, the passages 23 are inclined as low pressure at the point of ignition. This facilishown so that they enter the lower portion I4 of tates the passage of the spark between the electhe chamber tangentially causing a rapid whirltrodes and also places in the spark gap the moleing of the mixture as it enters and passes upcules of the mixture which kindle most readily ward in the chamber. The centrifugal effect of and thus increases the effectiveness and rapidity this whirling reduces still further the pressure of the ignition. The zone of low pressure is at the spark gap 22 as compared with that at the created by a reduced flow orifice surrounding the circumferential parts of the chamber. The

is spark gap and also by a swirling of the mixture swirling is nowhere obstructed as both the elecwithin the ignition chamber. Both the orifice trodes l0 and 2i lie on the axis of the chamber. and the swirling are also of value in protecting The spark between the electrodes l0 and 2| cothe insulation of the spark plug from excessive ours in the zone of lowest pressure and rapidly heat and thus increasing its durability. ignites the mixture in the chamber I4. The

An illustrative spark plug embodying my inburning mixture in the chamber is projected in 20 vention is shown in the accompanying drawing, jets through the passages 23 into the main body in which: of the mixture which is therebyrapidly ignited. Fig. 1 is a side view partly in axial section; The explosion pressure" developed in the Fig. 21s a bottom or inner end view, and cylinder on complete ignition of the mixture 25 Fig. 3 is a section on the line 33 of Fig. 1, momentarily causes burning gas to flow into the 25 looking in the direction of the arrows. chamber it through the passages 23. This hot The spark plug shown in the drawing includes gas swirls about the lower part I4 of the an insulator ll of ordinary construction, a metal chamber and then rises still swirling along the body H of special construction and two electrodes wall of the upper part M of the chamber before 1,21. The body I 2 has a nut portion I5, an exit strikes the insulator II. It thus traverses a 3 ternally threaded tubular portion l6 which exlong path over thick metal parts adapted to contends well beyond the innerend of the insulator duct away heat before it strikes the insulator. II, and a shield portion I l which substantially In this way, the portion of the insulator in the closes the innerend of the tubular portion but chamber is well protected against excessive contains passages hereinafter described. The heating. body l2 supports the insulator II in the usual The portion of the insulator II in the chamber manner, a nut l3 being used to secure the insuis well protected against excessive heat, as no lator to the body. The tubular portion. "5 and radiant heat can reach it from the cylinder and the Shield portion 17 0f the y p de a as the hot mixture entering through the pas- 40 chamber l4 enclosing the inner end of the insusages 23 swirls about in the lower part I4 of the 40 lator II and the spark gap 22 provided between chamber and then rises along the wall of the the electrodes l0 and 2|. The spark gap is at an upper part M of the chamber before it strikes intermediate point on the axis of the chamber !4 the insulator. It thus traverses a long path over but near the inner end of the chamber. An thick metal parts adapted to conduct away heat annular projection l8 on the inner wall of the before it strikes the insulator. 46

chamber l4 divides the chamber into an inner What-,1 claim is: portion I4 and an outer portion H connected by 1, A spark plug comprising an i l t body an orifice IQ of reduced diametersupporting the insulator and forming a casing When the Spark P is ou t in an engine providing a chamber enclosing the inner end of (A) cylinder or head in the usual manner, the inner the insulator and containing passages entering 50 Portion 0f the chamber is in eommunicathe inner end of said chamber, electrodes protion with the cylinder through passages or bores viding in the hamb r a spark gap extending 23 in the shield H. The mixture which flows into lengthwise of the chamber, and means other than the i ni i n c am r th u t s p ssa s du said electrodes providing in the chamber a reing the compression stroke of the engine is forced d d orifice surrgunding th spark gap.

2. A spark plug comprising an insulator, a body supporting the insulator and forming a casing providing a chamber enclosing the inner end of the insulator and containing passages entering the inner end of said chamber, electrodes providing in the chamber near the inner end thereof a spark gap extending lengthwise of the chamber, and means other than said electrodes providing in the chamber a reduced orifice surrounding the spark gap.

3. A spark plug comprising an insulator, a body supporting the insulator and forming a casing providing a chamber enclosing the inner end of the insulator and containing passages entering the inner end of said chamber tangentially, electrodes providing a spark gapin the chamber, and means providing in the chamber a reduced orifice surrounding the spark gap.

4. A spark plug comprising an insulator, a body supporting the insulator and forming a casing providing a'chamber enclosing the inner end of the insulator and containing passages entering the inner end of said chamber tangentially, electrodes providing a spark gap in the chamber on the axis of the chamber, and an internal annular projection on the casing dividing the chamber into two parts connected by a reduced orifice surrounding the spark gap.

5. A spark plug comprising an insulator, a body supporting the insulator and forming a casing providing a chamber enclosing the inner end of the insulator and containing passages entering the inner end of said chamber tangentially, electrodes provid ng a spark gap in the chamber on the axis of the chamber near the inner end thereof, and an internal annular projection on the.

casing dividing the chamber into two parts connected by a reduced orifice surrounding the spark gap.

6; A spark plug comprising 'aninsulator, a metal body supporting the insulator and forming a casing providing an enclosed chamber surrounding the inner end of the insulator and conof said tubular portion and increasing in thickness from its center towards its periphery and containing passages, an axial electrode carried by said shield and extending into the tubular portion of said body, and an axial electrode carried by the insulator and opposed to said other electrode to provide a spark gap.

WILLIAM HARPER, JR. 

